Pneumatic hammer.



No. 722,614. PATENTED 1 0, 1903.

S. OLDHAM & '.T. J'. PADBURY.

PNEUMATIG HAMMER.

APPLIoATIoN FILED un. 1a, 1901.

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UNITED STATES PATENT OFFICE.

SAMUEL OLDHAM AND .I OHN J. PADBURY, OF PHILADELPHIA, PENNSYL- VANIA, ASSIGNORS TO GEORGE OLDHAM AND SAMUEL OLDHAM, TRADING AS GEORGE OLDHAM da SON, OF FRANKFORD, PHILADEL- PHIA, PENNSYLVANIA.

PN EUMATIC HAM MER.

SPECIFICATION formingl part of Letters Patent No. 722,614, dated March 10, 1903.

i Application filed April l2, 1901. Serial No. 55,462. (No model.)

To all whom it may concern/.-

Be it known that We, SAMUEL OLDHAMand JOHN J. PADBURY, citizens of the United States, residing at Frankford, in the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have jointly invented certain new and usefullmprovements in Pneumatic Hammers, of which the following is a specification.

Our invention has relation to that class of pneumatic tools or hammers which are employed in the drilling, chipping, and dressing of stone or rock, as well as in riveting, calking, or hammering operations, and in such connection it relates to the construction and arrangement of such a tool or hammer.

The principal objects of our invention are, first, to provide in a pneumatic tool a reciprocating piston or hammer traversing the interior of a cylinder and a Valve having a range of movement in the upper end of said cylinder, the valve and piston controlling the volume of live air or fluid entering the cylinder, so that upon the downstroke of the piston the piston moves with a gradually-accelerated movement as more and more live air is admitted; second, to provide in such a tool means whereby upon the upstroke of the hammer or piston the travel of said hammer or piston is gradually checked; third, to provide in such a tool an arrangement of exhaust and live air ports and passages controlled by the valve and by the piston in such a manner that after the piston has been checked in its upper movement the valve is operated to reverse the movement of the piston, and, fourth, to provide in such a tool an arrangement of ports and passages for live and exhaust air and a piston and valve controlling the same,so that the shock of the hammer upon the casing of the tool is obviated Without impairing the force exerted by the hammer upon the tool.

The nature and scope of our invention will be more fully understood .from the following description, taken in connection with the accompanying drawings, forming part hereof, in which' Figure l is a longitudinal sectional View of a pneumatic tool or hammer embodying main features of our invention. Fig. 2 is an enlarged sectional view of the upper end of the tool or hammer and taken on the same plane as Fig. l, but illustrating the otherside of the interior of the tool. Fig. 3 is a cross-sectional view taken on the line 3 3of Fig. l. Fig. 4 is a longitudinal sectional View taken on the line 4 4 of Fig. 3 and looking toward the left of said Fig. 3, and Fig. 5 is horizontal sectional view taken on the line 5 5 of Fig. 3 and looking down upon the lower half of the tool. In the drawings our invention is illustrated as applied to a tool of the type illustrated in the Letters Patent No. 590,661, granted September 28, 1897, to Frank E. Harthan, in which the hammer or piston travels or has a stroke longer than the lengthr of said hammer or piston. Our tool also is provided with a grasping-handle provided with a valve controlling the admission of the air or fluid to the tool proper, such handle and valve being of a construction well known in the art.

Referring to the drawings, a represents the interior cylinder in which the hammer or piston b is adapted to travel, and c represents the outer ,casing or shell surrounding the cylinder b and also carrying the tool-holder c', in which the shank c2 of the tool c3 is held in any well-knownr manner. With the tool supported in the position illustrated in Figs. l and 3 near the upper end of the cylinder a and in the top of its wall is formed a slot or opening 0.', extending through the wall and in alinement with the port d, through which livev air or iuid passes from the handle d to the upper end of the cylinder b. This slot a is therefore the main inlet-port for live air. Diam'etrically opposite to but slightly above the main inlet-port a, another opening e is cut through the lower part of the wall of the cylinder and terminating in a longitudinal groove or channel e, formed between the cylinder a and casing c. This channel e' terminates in an opening e2, passing through the wall of the cylinder a at its extreme lower end. Avalve f, to be hereinafter more fully described, controls the opening or port e, so

that it may on the upstroke of the hammer b communicate with the entrance or main inlet-port a to permit live air to pass along the outside of the cylinder through the channel e' and to enter the cylinder through the opening e2 below the lower face of the hammer b and so that on the downstroke of said hammer b the port or opening e may communicate with the main exhaust port or outlet g. The channel e', by preference, is formed by cutting into the external periphery of the cylinder a, because that is the simplest and and easiest way to construct the tool. For the same reason all the longitudinally-arranged channels hereinafter described are likewise preferably cut in the external surface of said cylinder a. The valve fis provided with an upper head f', a lower head f2, and an intermediate head f3, so as to form between its ends f and j2 two openings or chambers f4 and f5. The heads f and f2 fit closely in the main bore of the cylinder ct. The upper headf' has a fiange f, which slides in an enlarged bore a2, forming a chamber at the upper end of the cylinder a. When the piston or hammer b is about to begin its upstroke, the valve f occupies the lowermost position in the cylinder a, so that its upper opening or chamber f4 forms a connection between the main live air inlet a and the opening e, leading live air to the channel e and port e2 to the bottom of the cylinder a below the hammer b. When, however, the valve f is lifted, as illustrated in Fig. 4, the intermediate head f3 of the valve closes the main liveair port 01,. At substantially right angles to the ports a' and e and in the upper end of the wall of the cylinder a are cut three openings h, h', and h2. The lower opening h of these openings is situated some distance below the lower head f2 of the valve f and is not controlled by said valve. The intermediate opening h is narrower than the openings yh and h2 and is adapted to be covered by the lower head 'f2 of the valve f when said valve is in its lowermost position and to be uncovered and below said head f2 when the valve f is in its uppermost position. The upper opening h2 is always in alinement with the lower chamber f5 of the valve f. The three openings h, h', and h2 are all connected by a longitudinal channel h3, as clearly illustrated in Figs. 2 and 5. Diametrically opposite the openings h, 72.', and h2 in the upper end of the wall of the cylinder a are cut two openings lo and k. The upper of these openings lc is in alinement with the main exhaust port or outlet g of the tool. y The lowermost opening lo' communicates by the longitudinal channel k2 with the opening k. The opening k is controlled in the movement of the valve f by the upper head f of said valve and is either closed by said upper head f or communicates with the upper chamber f 4 of said valve. The lower opening k is controlled by the lower head f 2 of the valve f and is either in communication with the lower chamber f5,

of the valve f or closed by the lower head f2 of said valve. When the opening 7.; is closed, the opening la communicates with the chamber f5 and when the opening la is closed the other openingk communicates with the chamber f4. The function of these openings h, h', and h2 and of the openings k and k' will be hereinafterifully described. The exterior of the cylinder o; is also provided with a longitudinal channel m, terminating at one end in the bore or chamber a2 and at its lower end in an opening m' cut through the Wall of the cylinder a at a point somewhat above the upper head of the hammer b when said hammer is in its lowermost position in striking engagement with the shank c2 of the tool c3. The opening fm' and channel m for convenience may be called the flip-opening and the flip-channel.

The operation of the tool is as follows: The hammer b having been forced down upon the shank c2 of the tool c3 rebounds sufficiently so that it will cover the flip-opening m'. At this moment the valve f is in its lowermost position, as indicated in Figs. 1 and 2. The main inlet a for live air communicates through the opening or chamber f4 of the valve f with the opening e, channel e', and port e2, and hence live air is forced to the lower end of the cylinder a below the lower head of the hammer b. The hammer travels upward in the cylindera until it clears the flip-opening m', when live air, partly diverted from the lower end of the cylinder a, enters the opening m and the channel m and is discharged into the chamber a2 above the flanged head of the Valve j' and serves to maintain the valve f in its lowermost position. The air above the upper head of the hammer b is forced by the travel of the hammer into the lower openingh and channel h3. I'n all positions of the valve fthe upper opening h2 of the channel h3 is always in communication with the chamber f5 of the valve f, and in the lowermost position of the valve f this chamber f5 is in open communication through the exhaust-opening lo' and channel k2 with the main exhaust port g. It follows, therefore, that for a portion of the travel upward of the hammer b the exhaustair in the cylinder a is forced out through the opening h into the exhaust-port g. When, however, the hammer b reaches the position illustrated in Fig. 4, the port or opening h is closed by the upper head of the hammer b, and therefore the air above the hammer b is IIO confined in the cylinder @between the upper Al and 2.

The valve f then moves until its intermediate head f3 first cuts ott entirely the port or main.

live-air inlet ct', and then brings said inlet ct into communication with the chamber f5 of the valvefat the precise moment the hammer b completes its upward stroke. This position is illustrated in Fig. 5. In this position live air passes from the inlet a' through the chamberfand through the upper opening h2 into the channel 71.3. As before explained, the lower opening 71. is closed by the hammer b; but the narrow intermediate opening h is cleared by the lower head f2 of the valve f. The live air thus passes through the narrow opening h' into the cylinder ct above the upper head of the hammer h. The hammer is thus initially forced downward under the pressure of but a portion of the live air until the hammer clears the lower opening h, when the full force of the live air or fluid acts upon the hammer and accelerates its movement toward the shank of the tool c3. As the hammer travels downward the exhaust in the cylinder a is forced out through the port c2, channel e', and port e into the upper chamber f4 of the valve f, fromwhence it passes into the opening lo and exhaust-outlet g. Vhen the upper head of the hammer b in its downward travel passes the lip-opening m', the live air, partly diverted from the cylinder d, passes through the opening m and channel m into the chamber a2 against the flanged head of the valve f and forces rsaid valve downward, so that the air-inlet a' is first closed by the valve and then brought into communication with the chamber f4 of the valvef, which position is indicated in Figs. The operation then continues as above described. The impact of the hammer or piston upon the shank of the tool materially assists in the shifting of the valve to its lowermost position.

Having thus described the nature and objects of our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In a pneumatic tool or hammer, a cylinder, a piston or hammer adapted to reciprocate in a portion of said cylinder, a valve adapted to reciprocate in the remaining portion of said cylinder and means controlled by the movement of both piston and valve for admitting live air or iiuid to the cylinder above the piston on its downstroke in varying volume, so that the downward movement of the piston is accelerated after it has begun to travel.

2. In a pneumatic tool or hammer, a cylinder, a piston adapted to reciprocate therein, a valve having a range of movement beyond the upstroke ot the piston, partly in the upper end of the cylinder and partly in an enlarged chamber forming a continuation of said cylinder, combined with means for directing the pressure of live fiuid toward an upper enlarged head, formed on the valve, moving in said chamber, and means for compressing the exhaust within the cylinder between the piston and a lower Vsolid head formed on said valve, both means beingcontrolled by the piston during its upstroke toward the valve.

3. In a pneumatic tool or hammer, a cylinder, a piston adapted to reciprocate in a portion of said cylinder, a valve adapted to reciprocate in the remaining portion of said cylinder and having a lower head or end closing the inner bore of said cylinder and means controlled by the piston and valve for rst checking the upward movement of the piston by cushioning the air between said piston and lower head of said valve and then shifting the valve to reverse the movement of the piston.

4. In a pneumatic tool or hammer, a cylinder, a piston or hammer having a range of movement therein, and a valve located within the cylinder above the hammer and in the path thereof, said valve and piston mutually coperating to control each other and said valve having a lower head completely closing the inner bore of said cylinder.

5. In a pneumatic tool or hammer, a cylinder, a piston or hammer having a range of movement. therein, a yvalve traversing the upper end of the cylinder and having a lower head closing the inner bore of the cylinder, said valve arranged in the path of the piston or hammer, and moving in the same direction as the piston or hammer in the reciprocation thereof, and said piston or hammer and valve mutually coperating to control each other.

6. In a tool or hammer of the character described, a cylinder, wherein the hammer or piston is adapted to reciprocate, a valve arranged in the cylinder and having a lower head closing the inner bore of the cylinder at a point beyond the stroke of the piston or hammer, said valve having lower, upper and intermediate heads, and chambers or openings formed between the intermediate and end heads and said valves and its heads controlling the actuation of the piston or hammer, and said piston in conjunction with the heads and chambers controlling the operation of said valve. y

In testimony whereof we have hereunto set our signatures in the presence of two sub-` scribing witnesses.

SAMUEL OLDHAM. JOHN'v J. PADBURY.

Witnesses: l

WALTON R. BILEs, EDWD. F. SHIELDs.

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